1. Field of the Invention
This invention relates to a flash apparatus of the type which includes a light emitting section having a predetermined irradiation angle and an irradiating direction changing mechanism for changing the irradiating direction of the light emitting section.
2. Description of the Prior Art
A flash apparatus is already known wherein the irradiating direction of a light emitting section is changed by an irradiating direction changing mechanism. In an exemplary one of conventional flash apparatus of the type mentioned, the light emitting section is mounted for pivotal motion around a vertical axis or a horizontal axis on a flash apparatus body. When such flash apparatus is used, an operator holds, for example, and pivots the light emitting section suitably to perform so-called bounce photographing wherein flashlight emitted from the flash apparatus is irradiated not directly upon a subject but reflected light from some other article is used or to arbitrarily change the light distribution characteristic of flashlight to a photographing screen.
The conventional flash apparatus, however, is disadvantageous in the following points.
In particular, it often takes place that, upon photographing with a camera with which such flash apparatus is used, a photographing area includes, in addition to an aimed subject, some other body which is positioned nearer to the camera than the aimed subject or that a photographing area includes some indoor subjects and some outdoor subjects. In such an instance, if the flash apparatus emits flashlight to an entire photographing area as an irradiation range, some of subjects may possibly be photographed in an over exposure or under exposure condition. Therefore, the irradiation range of the flash apparatus is preferably displaced with respect to a photographing area when necessary.
With such conventional flash apparatus as described above, however, while the light emitting section is mounted for pivotal motion on the flash apparatus body, a photographer must manually make such pivotal motion of the light emitting section. Thus, when the irradiation range of the flash apparatus must be displaced in such a photographing situation as described above, it is cumbersome to make such manual pivoting motion of the light emitting section, and besides, a shutter chance may be lost. In addition, the amount of such pivotal motion almost depends upon the sixth sense of a photographer, and accordingly, even if the light emitting section is pivoted, appropriate exposure may not always be achieved. Besides, when a proximate body is included at an end portion of a photographing area, a photographer may not be aware of such body and may perform flashlight photographing while keeping the light emitting section of the flash apparatus in an ordinary posture, which will lead to failure in photographing.
Such possible failure in photographing arising from the presence of an unexpected proximate body likely takes place when the flash apparatus is used together with a camera which includes a full size lens and employs an ordinary 35 mm size film but has a function of photographing in a special area such as, for example, a panorama area which is defined by sectioning at least part of an exposeable area of such film itself in a vertical direction so as to prevent exposure to light.
Meanwhile, in order to allow the light emitting section of the flash apparatus to be automatically pivoted or displaced to a suitable position eliminating such cumbersome manual operation by a photographer as described above, the camera must have an automatic focusing (AF) function of automatically focusing a photographing optical system in response to a position of a focus detected in accordance with, for example, a phase difference detecting method by TTL (through the lens) light measurement. An exemplary one of such AF apparatus is shown in FIG. 44.
Referring to FIG. 44, the AF apparatus shown includes a distance measuring module 223 for receiving light from a subject thereon. Light from a subject passes through a photographing lens (not shown) of a single lens reflex camera in which the AF apparatus is incorporated and then through a main mirror 221 and is then refracted by a sub mirror 222. The distance measuring module 223 includes a condenser lens 225 disposed in the proximity of a film equivalent plane (image plane) 224 on which an image of a subject is formed, a separator lens 226 for dividing such image, and an image pickup element 227 constituted from a CCD (charge coupled device) or the like for re-forming the image via the separator lens 226 and generating a focus position signal. It is to be noted that, in the arrangement shown in FIG. 44, a mirror 228 is interposed between the condenser lens 225 and the separator lens 226 to bend the optical axis of such image light.
In a region forwardly of and corresponding to an area defined by a pair of upper and lower edges of a standard screen frame 210 which partitions an area of a film F to be exposed to light, more particularly, as a location below an optical axis 311 of the photographing lens, in a region corresponding to an exposeable area (dimension C) of an ordinary film between the optical axis 311 and a parallel line 312 passing the lower edge of the standard screen frame 210, there is disposed no fixed member which may intercept light. This is because, otherwise if some fixed member which intercepts light is present in such region, a film will not be exposed partly to light. Accordingly, the distance measuring module 223 including the condenser lens 225 is not disposed at a location nearer to the optical axis 311 than the distance C.
On the other hand, if the film equivalent plane (image plane) 224 is located nearer to the condenser lens 225, then the diameter of the condenser lens 225 can be reduced as much (substantially to the size of the image plane). However, since light expands as the distance between the film equivalent plane 224 and the condenser lens 225 increases, the condenser lens 225 must have a greater diameter as much. Therefore, in order to minimize the diameter of the condenser lens 225 which must be located outside or below the line 312 spaced by the distance C from the optical axis 311 as described above, the film equivalent plane 224 is located as near as possible to the line 312.
By the way, the sub mirror 222 is disposed on the optical axis 311 of the photographing lens in front of a film F, and naturally the distance l between the sub mirror 222 and the film F is made equal to the distance l between the sub mirror 222 and the film equivalent plane 224. Accordingly, the sub mirror 222 cannot be disposed nearer to the film F than the distance C. This makes one of restrictions to minimization of dimensions of the camera in the depthwise direction and the vertical direction. As a result, it is difficult to eliminate from an upper face of the camera a projection in which a pentagonal prism is accommodated.
It is to be noted that a camera is also known which employs an ordinary 35 mm size film and can take a photograph of a special area, such as, for example, a panorama size having a generally horizontally elongated profile using a special screen frame which intercepts light to at least part of an exposeable area of a film itself in a vertical direction so as to prevent exposure to light. Such camera, however, does not pay special attention to miniaturization in construction and elimination of a projection for a pentagonal prism.